Clippy: Backport `needless_return` fix
r? `@Manishearth`
This cherry-picks https://github.com/rust-lang/rust-clippy/pull/13464, so that it gets into master and with that into `beta` tomorrow, so that the bug in this lint doesn't hit `beta`.
Changes look quite big, but most of them are whitespace changes because of the introduction of an `_inner` function. In reality it only adds 2 checks.
Introduce SolverRelating type relation to the new solver
Redux of #128744.
Splits out relate for the new solver so that implementors don't need to implement it themselves.
r? lcnr
LLVM and Cranelift disagree about how to return values that don't fit
in the registers designated for return values. LLVM will force the
entire return value to be passed by return area pointer, while
Cranelift will look at each IR level return value independently and
decide to pass it in a register or not, which would result in the
return value being passed partially in registers and partially through
a return area pointer.
While Cranelift may need to be fixed as the LLVM behavior is generally
more correct with respect to the surface language, forcing this
behavior in rustc itself makes it easier for other backends to conform
to the Rust ABI and for the C ABI rustc already handles this behavior
anyway.
In addition LLVM's decision to pass the return value in registers or
using a return area pointer depends on how exactly the return type is
lowered to an LLVM IR type. For example `Option<u128>` can be lowered
as `{ i128, i128 }` in which case the x86_64 backend would use a return
area pointer, or it could be passed as `{ i32, i128 }` in which case
the x86_64 backend would pass it in registers by taking advantage of an
LLVM ABI extension that allows using 3 registers for the x86_64 sysv
call conv rather than the officially specified 2 registers.
This adjustment is only necessary for the Rust ABI as for other ABI's
the calling convention implementations in rustc_target already ensure
any return value which doesn't fit in the available amount of return
registers is passed in the right way for the current target.
The `Box<T: Default>` impl currently calls `T::default()` before allocating
the `Box`.
Most `Default` impls are trivial, which should in theory allow
LLVM to construct `T: Default` directly in the `Box` allocation when calling
`<Box<T>>::default()`.
However, the allocation may fail, which necessitates calling `T's` destructor if it has one.
If the destructor is non-trivial, then LLVM has a hard time proving that it's
sound to elide, which makes it construct `T` on the stack first, and then copy it into the allocation.
Create an uninit `Box` first, and then write `T::default` into it, so that LLVM now only needs to prove
that the `T::default` can't panic, which should be trivial for most `Default` impls.
Back from burnout
This reverts commit 5ea7044d72. I needed some time free from reviewing to focus on the Project Goal and myself.
Now I'm much better, and we can continue reviewing!
I hope that I can approve this myself 😅
changelog: none
Apple: Avoid redundant `-Wl,-dylib` flag when linking
Seems to have been introduced all the way back in e338a4154b, but should be redundant, `-dynamiclib` should already make `cc` set `-dylib` when linking.
Spotted this while trying to get `-Clinker-flavor=gcc` and `-Clinker-flavor=ld` closer together, not that important to fix.
`@rustbot` label O-apple
fix/update teach_note from 'escaping mutable ref/ptr' const-check
The old note was quite confusing since it talked about statics, but the message is also shown for consts. So let's reword to something that is true for both of them.
Fix a few relative paths in rustc doc
## Changes
- Don't inline the doc for re-exporting some structs that have relative paths in doc.
## Context
See #124028.
- Most of the relative links in rustdoc are there because of circular import (so syntax like `[MyType]: rustc_foo::bar` is difficult to achieve when we cannot import `rustc_xxx` due to circular import)
- Here, I disable new links for re-exports. I think it's fine for re-exported items in `hir::*`.
- There is a few more relative links in other `rustc` crates, however they are not addressed in this PR, as they are not re-exported and/so the relative paths are working.
Closes#124028.
r? `@fmease`
Let me know if I miss anything or there's any other way to address this issue.
LLVM 20 split out what used to be called b16b16 and correspond to aarch64
FEAT_SVE_B16B16 into sve-b16b16 and sme-b16b16.
Add sme-b16b16 as an explicit feature and update the codegen accordingly.
Don't warn on proc macro generated code in `needless_return`
Fixes#13458Fixes#13457Fixes#13467Fixes#13479Fixes#13481Fixes#13526Fixes#13486
The fix is unfortunately a little more convoluted than just simply adding a `is_from_proc_macro`. That check *does* fix the issue, however it also introduces a bunch of false negatives in the tests, specifically when the returned expression is in a different syntax context, e.g. `return format!(..)`.
The proc macro check builds up a start and end pattern based on the HIR nodes and compares it to a snippet of the span, however that would currently fail for `return format!(..)` because we would have the patterns `("return", <something inside of the format macro>)`, which doesn't compare equal. So we now return an empty string pattern for when it's in a different syntax context.
"Hide whitespace" helps a bit for reviewing the proc macro detection change
changelog: none
Don't warn on proc macro generated code in `needless_return`
Fixes#13458Fixes#13457Fixes#13467Fixes#13479Fixes#13481Fixes#13526Fixes#13486
The fix is unfortunately a little more convoluted than just simply adding a `is_from_proc_macro`. That check *does* fix the issue, however it also introduces a bunch of false negatives in the tests, specifically when the returned expression is in a different syntax context, e.g. `return format!(..)`.
The proc macro check builds up a start and end pattern based on the HIR nodes and compares it to a snippet of the span, however that would currently fail for `return format!(..)` because we would have the patterns `("return", <something inside of the format macro>)`, which doesn't compare equal. So we now return an empty string pattern for when it's in a different syntax context.
"Hide whitespace" helps a bit for reviewing the proc macro detection change
changelog: none
Don't warn on proc macro generated code in `needless_return`
Fixes#13458Fixes#13457Fixes#13467Fixes#13479Fixes#13481Fixes#13526Fixes#13486
The fix is unfortunately a little more convoluted than just simply adding a `is_from_proc_macro`. That check *does* fix the issue, however it also introduces a bunch of false negatives in the tests, specifically when the returned expression is in a different syntax context, e.g. `return format!(..)`.
The proc macro check builds up a start and end pattern based on the HIR nodes and compares it to a snippet of the span, however that would currently fail for `return format!(..)` because we would have the patterns `("return", <something inside of the format macro>)`, which doesn't compare equal. So we now return an empty string pattern for when it's in a different syntax context.
"Hide whitespace" helps a bit for reviewing the proc macro detection change
changelog: none
disable `download-rustc` if LLVM submodule has changes in CI
We can't use CI rustc while using in-tree LLVM (which happens in LLVM submodule update PRs) and this PR handles that by ignoring CI-rustc in CI and failing in non-CI environments.
